100
Continue
The server has received the request headers and the client should send the body. Used with Expect: 100-continue.
RFC 9110 · Link
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HTTP Status Codes — Complete List
Every HTTP response status code explained in plain English. Search by number or keyword, or filter by class — from 1xx informational to 5xx server errors.
1xx Informational
The request was received and is being processed.
101
Switching Protocols
The server is switching protocols as requested by the Upgrade header — for example, to WebSocket.
RFC 9110 · Link
102
Processing
The server has accepted the request but hasn't finished it yet (WebDAV). Rarely used today.
RFC 2518 · Link
103
Early Hints
Lets the browser start preloading resources (via Link headers) while the server prepares the final response.
RFC 8297 · Link
2xx Success
The request was received, understood and accepted.
200
OK
The request succeeded. The body contains the result — the resource for GET, the outcome for POST.
RFC 9110 · Link
201
Created
The request succeeded and a new resource was created. The Location header usually points to it.
RFC 9110 · Link
202
Accepted
The request was accepted for processing but isn't finished — common for background jobs and queues.
RFC 9110 · Link
203
Non-Authoritative Information
The response was modified by a proxy and isn't exactly what the origin server sent.
RFC 9110 · Link
204
No Content
The request succeeded and there's no body to return. Common for DELETE and for PUT updates.
RFC 9110 · Link
205
Reset Content
The request succeeded and the client should reset the form or view that sent it.
RFC 9110 · Link
206
Partial Content
Only part of the resource is returned, as asked for by a Range header — used for resumable downloads and video streaming.
RFC 9110 · Link
207
Multi-Status
The body contains several status codes for several operations (WebDAV).
RFC 4918 · Link
208
Already Reported
Members of a WebDAV binding were already listed earlier in the response.
RFC 5842 · Link
226
IM Used
The server applied instance manipulations (such as a delta) to the response.
RFC 3229 · Link
3xx Redirection
Further action is needed — usually following another URL.
300
Multiple Choices
There are several possible responses and the client should choose one.
RFC 9110 · Link
301
Moved Permanently
A permanent redirect — the resource has a new URL, given in the Location header. Browsers and search engines update their links. The method may change from POST to GET.
RFC 9110 · Link
302
Found
A temporary redirect — the resource is at another URL for now (Location header). Browsers usually follow it with GET.
RFC 9110 · Link
303
See Other
A redirect telling the client to GET another URL — typically used after a form POST to show a result page.
RFC 9110 · Link
304
Not Modified
The cached copy is still valid, so no body is sent. A response to If-None-Match or If-Modified-Since.
RFC 9110 · Link
307
Temporary Redirect
Temporarily at another URL — and unlike 302, the method and body must stay the same.
RFC 9110 · Link
308
Permanent Redirect
Permanently at another URL — and unlike 301, the method and body must stay the same.
RFC 9110 · Link
4xx Client error
The request has a problem the client needs to fix.
400
Bad Request
The server can't process the request because it's malformed — invalid JSON, missing fields or bad syntax.
RFC 9110 · Link
401
Unauthorized
Authentication is required or has failed. Despite the name, it means unauthenticated — send valid credentials.
RFC 9110 · Link
402
Payment Required
Reserved for future use. Some APIs use it for billing or quota problems.
RFC 9110 · Link
403
Forbidden
The server understood who you are but refuses access. Logging in again won't help.
RFC 9110 · Link
404
Not Found
The resource doesn't exist at this URL — or the server is hiding that it exists.
RFC 9110 · Link
405
Method Not Allowed
The URL exists but doesn't support this method (for example, POST to a read-only endpoint). The Allow header lists valid methods.
RFC 9110 · Link
406
Not Acceptable
The server can't produce a response matching the Accept headers sent by the client.
RFC 9110 · Link
407
Proxy Authentication Required
Like 401, but the client must authenticate with a proxy.
RFC 9110 · Link
408
Request Timeout
The server gave up waiting for the client to finish sending the request.
RFC 9110 · Link
409
Conflict
The request conflicts with the current state — for example, a duplicate record or an edit conflict.
RFC 9110 · Link
410
Gone
The resource was deliberately and permanently removed. Unlike 404, it won't come back.
RFC 9110 · Link
411
Length Required
The server needs a Content-Length header.
RFC 9110 · Link
412
Precondition Failed
A condition in the request headers (such as If-Match) wasn't met — often used to prevent lost updates.
RFC 9110 · Link
413
Content Too Large
The request body is larger than the server allows — for example, an upload over the size limit.
RFC 9110 · Link
414
URI Too Long
The URL is longer than the server will handle — often caused by very long query strings.
RFC 9110 · Link
415
Unsupported Media Type
The server doesn't support the body's format. Check the Content-Type header.
RFC 9110 · Link
416
Range Not Satisfiable
The Range requested is outside the size of the resource.
RFC 9110 · Link
417
Expectation Failed
The server can't meet the Expect request header.
RFC 9110 · Link
418
I'm a teapot
An April Fools' joke from the Hyper Text Coffee Pot Control Protocol. Some sites use it for playful errors.
RFC 2324 · Link
421
Misdirected Request
The request reached a server that can't respond for this host — seen with HTTP/2 connection reuse.
RFC 9110 · Link
422
Unprocessable Content
The syntax is fine but the content fails validation — common in REST APIs for field errors.
RFC 9110 · Link
423
Locked
The resource is locked (WebDAV).
RFC 4918 · Link
424
Failed Dependency
The request failed because an earlier request it depended on failed (WebDAV).
RFC 4918 · Link
425
Too Early
The server won't process a request that might be replayed (TLS early data).
RFC 8470 · Link
426
Upgrade Required
The client must switch to another protocol, given in the Upgrade header.
RFC 9110 · Link
428
Precondition Required
The server requires conditional requests (such as If-Match) to prevent lost updates.
RFC 6585 · Link
429
Too Many Requests
Rate limit exceeded. The Retry-After header says how long to wait before trying again.
RFC 6585 · Link
431
Request Header Fields Too Large
The headers are too big — often caused by too many or oversized cookies.
RFC 6585 · Link
451
Unavailable For Legal Reasons
Access is blocked for legal reasons, such as a court order or government censorship.
RFC 7725 · Link
5xx Server error
The server failed to handle a valid request.
500
Internal Server Error
A generic server error — something unexpected went wrong, such as an unhandled exception. Check the server logs.
RFC 9110 · Link
501
Not Implemented
The server doesn't support the functionality needed — for example, an unknown method.
RFC 9110 · Link
502
Bad Gateway
A gateway or proxy (such as Nginx or a load balancer) got an invalid response from the upstream server — often because the app crashed or isn't running.
RFC 9110 · Link
503
Service Unavailable
The server is temporarily unable to handle requests — overloaded or down for maintenance. Retry-After may say when to try again.
RFC 9110 · Link
504
Gateway Timeout
A gateway or proxy didn't get a response from the upstream server in time — often a slow query or a hung app.
RFC 9110 · Link
505
HTTP Version Not Supported
The server doesn't support the HTTP version used in the request.
RFC 9110 · Link
506
Variant Also Negotiates
A server configuration error in content negotiation.
RFC 2295 · Link
507
Insufficient Storage
The server can't store what's needed to complete the request (WebDAV).
RFC 4918 · Link
508
Loop Detected
The server found an infinite loop while processing the request (WebDAV).
RFC 5842 · Link
510
Not Extended
Further extensions are required for the server to fulfil the request.
RFC 2774 · Link
511
Network Authentication Required
You need to sign in to the network first — typical of hotel or airport Wi-Fi captive portals.
RFC 6585 · Link
When should you use the HTTP Status Codes?
- Finding out what an error like 403, 422 or 502 actually means
- Choosing the right status code when designing a REST API
- Debugging redirects, caching (304) and rate limits (429)
How to use the HTTP Status Codes
- 1
Search
Type a code (404), a class (5xx) or words like redirect or rate limit.
- 2
Filter by class
Show only 2xx successes, 4xx client errors and so on.
- 3
Read the explanation
Each code says what it means, when it's used and which spec defines it.
- 4
Share a code
Use the Link under a code to share it directly, for example /http-status-codes#429.
Examples
Searching for 'redirect'
Search
redirect
Matches
301 Moved Permanently 302 Found 303 See Other 307 Temporary Redirect 308 Permanent Redirect
Common errors and how to fix them
401 or 403?- 401 means you aren't authenticated (log in or send a token). 403 means you are, but you aren't allowed.
502 or 504?- Both come from a proxy or load balancer. 502 means the app sent a bad response or isn't running; 504 means it didn't answer in time.
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HTTP Status Codes FAQ
1xx informational, 2xx success, 3xx redirection, 4xx client errors (a problem with the request) and 5xx server errors (the server failed).
301 is a permanent redirect — browsers and search engines update to the new URL. 302 is temporary. Use 308 and 307 if the request method must not change.
The server has nothing at that URL. If the page was removed deliberately and won't return, 410 Gone is more precise.
400 for a request that can't be parsed (bad JSON or syntax). 422 when it parses but fails validation, such as a missing or invalid field.
You've hit a rate limit. Wait for the time in the Retry-After header before trying again.
An unexpected error on the server, such as an unhandled exception or a bug. The details are in the server's logs, not the response.